GRAMMOCERAS STRIATULUM. 178 



seems tliat the name should be written toarciensis. A term, " Toarcien," derived 

 from the same source was used by d'Orbigny for the strata between the " Liasien " 

 and " Bajocien." Such strata are equal to the Upper Lias, the Sands, and the 

 lower part of the Inferior Oolite of English Geologists.'^ 



One of the commoner species in the Jurense-zone, Gramm. toarcense occurs — at 

 least in Gloucestershire — more frequently than Gramm. striatulum^ with which it is 

 always associated. I have collected it along the flanks of the Cotteswolds at 

 Buckholt Wood, Coaley Wood, Stiuchcombe, North Nibley, Wotton-under-Edge, 

 Sodbury, and many intermediate places in Gloucestershire; in Somerset at the 

 Lyncombe cutting near Bath ; and Mr. B. Wilson sent for my inspection a 

 specimen from Dundry in the same county. In Yorkshire the. species occurs at 

 the Peak, and, I believe, not unfrequently. 



Plate XXVIII, fig. 4, exhibits the side view of a fine, adult, extreme form of 

 Gramm. toarcense with very coarse ribs and the sigmoidal termination ; fig. 5 

 represents the ventral portion of the termination, and also the broad square 

 ventral area ; fig. 6 shows the simple suture-line taken from this specimen. In 

 fig. 7 is seen the side view of another form of which the ribs are not so coarse and 

 are inconspicuous on the inner third of the whorl ; fig. 8, illustrates the front view 

 with a characteristic depressed area each side of the carina. Figs. 9, 10 give two 

 views of another specimen. Figs. 11 and 12 represent the inner whorls of the 

 species enlarged about four times ; they clearly indicate the Goniatite-stage, as 

 also does the suture-line, fig. 13. Fig. 14 gives the side view of a coarsely-ribbed 

 form, which, however, in its sharpened ventral area (fig. 15) partakes of the 

 characters of Gramm. striatidum. In order to express this I have described it as 

 Gramm. ioarcense-striatulum. Plate XXXIV, fig. 12, shows a variety with forked 

 ribs. 



Grammoceras striatdlum (Soiverhy). PI. XXVI, figs. 7 — 10 ; PI. XXVIII, 



figs. 16—21 ; PI. A, figs. 43, 44. 



1825. Ammonites steiatulus, Sowerby. Min. Concli., vol. v, pi. ccccxxi, fig. 1, 



p. 23. 

 1856. — — Oppel. Jurat'., p. 248. 



1864. — STBiATULTJS, SeehacJi. Hann. Jura, p. 140 (pars). 



1867. Grammoceras striatuldm, Ri/att. Cepli. ; Bull. Mua. Comp. ZooL, p. 99. 



' See my paper on tlie " The Cotteswold, Midford, and Yeovil Sands, and the Division between 

 Lias and Oolite," ' Quart. Journ. Geol. Soc.,' vol. xlv, pp. 440 — 474. 



2 Hitherto I have used the latter name for both forms indiscriminately. 



